This invention relates generally to a borescope or endoscope for providing full color video images of inaccessible objects of the type having an elongated insertion tube for passage into remote cavities and more particularly to an illumination system for portable, compact, battery-operated borescopes.
A borescope is generally characterized as an elongated flexible insertion tube with a viewing head at the distal end and a control and processing section at the proximal end. The control section has generally included one or two pairs of control cables extending from a bendable tube section adjacent the distal end through the remainder of the insertion tube to connect to the steering control mechanism in the control section. Various devices have been provided in the prior art for realizing a full color video picture of a target situated within a remote cavity. These devices have gradually improved over time to where today most devices of this type employ an external light source conveyed to the image viewing head by fiber optic bundles, together with a solid state image sensor and lens system positioned in the distal end of the insertion tube operatively connected to an external video processing system and standard television format display.
Endoscope/borescope systems of this general type have been disclosed in various patents owned by a common assignee of the present applicant, such as U.S. Pat. No. 4,253,447 to Moore et al.; U.S. Pat. No. 4,261,344 to Moore et al; and U.S. Pat. No. 4,491,865 to Danna et al. Another endoscope system is shown in U.S. Pat. No. 4,621,618 to Omagari, which describes a central control/display/light station, and a drive motor body for the insertable endoscope portion. The central control has a joystick actuated motor drive circuit for the motor mounted adjacent to and which manipulates the wire controlled bendable section of the insertion tube. This rather large cumbersome system requires a paramedic to handle the endoscope while the doctor operates the device from the control station. Also, the apparatus obviously is not portable.
As part of the need for greater flexibility and portability, the control of the steering function of a borescope has had to be simplified and improved both from an operating, as well as adjustability and maintenance viewpoint. In addition, the illumination system of the portable borescope has to be able to operate for extended periods of time without access to commercial power to provide optimum illumination of the object being viewed. As is well known in the art, the greater the power demands of a device, the larger the batteries that are required to power the unit and the more cumbersome the unit becomes in terms of portability and access to areas of restricted space. One of the major power consuming devices in a borescope/endoscope system is the lamp used to provide illumination through the fiber optic bundles to the viewing head for illuminating the object to be viewed. Generally speaking, the longer the insertion tube and the greater the distance from the viewing head to the object to be viewed, the greater the light output that is required, and the greater the power consumption and hence battery drain. Frequently, lamps of several hundred watt output are required to properly illuminate an object to be viewed, which poses a very significant drain on a small, compact battery pack for a portable borescope system.